International Dredging Review

International Dredging Review

Trimble has introduced the Virtual Reference Station (VRS) which allows users to achieve long-range real-time kinematic (RTK) precision via wireless communications in the field. The VRS enables centimeter-level positioning without the need to set up a local reference station.

The announcement was made on September 20 at the Institute of Navigation GPS 2000 conference in Salt Lake City.

The VRS developed by Spectra Precision’s subsidiary TerraSat consists of software and a network of Trimble GPS receivers communicating with a control center. The VRS software uses the data to calculate GPS error corrections that are applicable over a wide area. Their error corrections are transmitted via wireless communication devices (radios or cellular telephones) to users in the field within the network area. Users can retrieve stored GPS correction data from the control center via the Internet for post-processing.

VRS technology overcomes previous limitations with high precision GPS. The system significantly reduces systematic errors in the reference station data to improve reliability and operating range. This allows a user to increase the distance between the rover receiver and the physical reference stations while improving on-the-fly (OTF) initialization times. Traditionally for precise GPS applications – surveying construction precision farming and high accuracy Geographic Information System (GIS) – roving receivers required a reference station within 10 kilometers to ensure centimeter-level accuracy. With VRS users can operate at distances up to 50 kilometers without degrading accuracy – at least three times greater than before.

GPS Infrastructure consists of reference stations (single or networked) and application software that enables users to determine their position at various levels of accuracy in either real-time or through post-processing. Trimble and Spectra Precision provide complete GPS infrastructure solutions – hardware software integration and support.

Trimble was founded in 1978 and is a leader in the development of GPS products for a wide range of applications. This year the company acquired Spectra Precision a provider of construction lasers machine control systems optical surveying instruments and related software. This acquisition broadened Trimble’s portfolio of positioning solutions for the engineering construction and agriculture markets.